1. Field of Disclosure
The present disclosure relates to vibrating tools in general, and in particular to a method and apparatus for vibrating a downhole tool in a drill string.
2. Description of Related Art
In the field of drilling, friction may frequently impair the ability of the drill string to be advanced within the hole. For example, highly deviated holes or horizontal drilling cannot rely on the weight of the drill pipe alone to overcome friction from the horizontal pipe resting against the wall of the hole.
Conventional vibration tools have alternatingly increased the pressure of the drilling fluid within the drill string by cyclically blocking and unblocking the flow of the drilling fluid within the drill string. Such devices accordingly cyclically increase the pressure of the drilling fluid within the drill string and then release it. Such devices disadvantageously require a high supply pressure over and above the supply pressure for the drilling fluid. This increases cost and complexity of the machinery required to support this operation. In addition, many conventional vibration tools involve complex downhole systems and devices which may be more prone to breakage.
Many such conventional vibration tools also create backpressure in the drilling fluid supply. This has the negative consequences of requiring supply pumps of greater capacity and also reduces the supply pressure to the drilling bit. Still other apparatuses have utilized blunt mechanical impacts which increases the wear life and the complexity of the design.